Dataset Information

Fabrication of Au-Ag nanocage@NaYF₄@NaYF₄:Yb,Er Core-Shell Hybrid and its Tunable Upconversion Enhancement.

ABSTRACT: Localized electric filed enhancement by surface plasmon resonance (SPR) of noble metal nanoparticles is an effective method to amplify the upconversion luminescence (UCL) strength of upconversion nanoparticles (UCNPs), whereas the highly effective UCL enhancement of UCNPs in colloids has not been realized until now. Here, we designed and fabricated the colloidal Au-Ag nanocage@NaYF₄@NaYF₄:Yb,Er core-shell hybrid with different intermediate thickness (NaYF₄) and tunable SPR peaks from visible wavelength region to NIR region. After the optimization of the intermediate spacer thickness (~7.5?nm) of NaYF₄ NPs and the SPR peak (~950?nm) of noble metal nanoparticles, an optimum enhancement as high as ~25 folds was obtained. Systematic investigation indicates that UCL enhancement mainly originates from the influence of the intermediate spacer and the coupling of Au-Ag nanocages with the excitation electromagnetic field of the UCNPs. Our findings may provide a new thinking on designing highly effective metal@UCNPs core-shell hybrid in colloids.

SUBMITTER: Chen X

PROVIDER: S-EPMC5247729 | biostudies-literature | 2017 Jan

REPOSITORIES: biostudies-literature

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Publications

Fabrication of Au-Ag nanocage@NaYF4@NaYF4:Yb,Er Core-Shell Hybrid and its Tunable Upconversion Enhancement.

Chen Xu X Zhou Donglei D Xu Wen W Zhu Jinyang J Pan Gencai G Yin Ze Z Wang He H Zhu Yongsheng Y Shaobo Cui C Song Hongwei H

Scientific reports 20170120

Localized electric filed enhancement by surface plasmon resonance (SPR) of noble metal nanoparticles is an effective method to amplify the upconversion luminescence (UCL) strength of upconversion nanoparticles (UCNPs), whereas the highly effective UCL enhancement of UCNPs in colloids has not been realized until now. Here, we designed and fabricated the colloidal Au-Ag nanocage@NaYF4@NaYF4:Yb,Er core-shell hybrid with different intermediate thickness (NaYF4) and t ...[more]

PMID: 28106128

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Project description:Lanthanide-doped upconversion nanoparticles (UCNPs) have a unique capability of upconverting near-infrared (NIR) excitation into ultraviolet, visible, and NIR emission. Conventional UCNPs composed of NaYF4:Yb3+/Er3+(Tm3+) are excited by NIR light at 980 nm, where undesirable absorption by water can cause overheating or damage of living tissues and reduce nanoparticle luminescence. Incorporation of Nd3+ ions into the UCNP lattice shifts the excitation wavelength to 808 nm, where absorption of water is minimal. Herein, core-shell NaYF4:Yb3+/Er3+@NaYF4:Nd3+ nanoparticles, which are doubly doped by sensitizers (Yb3+ and Nd3+) and an activator (Er3+) in the host NaYF4 matrix, were synthesized by high-temperature coprecipitation of lanthanide chlorides in the presence of oleic acid as a stabilizer. Uniform core (24 nm) and core-shell particles with tunable shell thickness (~0.5-4 nm) were thoroughly characterized by transmission electron microscopy (TEM), energy-dispersive analysis, selected area electron diffraction, and photoluminescence emission spectra at 808 and 980 nm excitation. To ensure dispersibility of the particles in biologically relevant media, they were coated by in-house synthesized poly(ethylene glycol) (PEG)-neridronate terminated with an alkyne (Alk). The stability of the NaYF4:Yb3+/Er3+@NaYF4:Nd3+-PEG-Alk nanoparticles in water or 0.01 M PBS and the presence of PEG on the surface were determined by dynamic light scattering, ζ-potential measurements, thermogravimetric analysis, and FTIR spectroscopy. Finally, the adhesive azidopentanoyl-modified GGGRGDSGGGY-NH2 (RGDS) peptide was immobilized on the NaYF4:Yb3+/Er3+@NaYF4:Nd3+-PEG-Alk particles via Cu(I)-catalyzed azide-alkyne cycloaddition. The toxicity of the unmodified core-shell NaYF4:Yb3+/Er3+@NaYF4:Nd3+, NaYF4:Yb3+/Er3+@NaYF4:Nd3+-PEG-Alk, and NaYF4:Yb3+/Er3+@NaYF4:Nd3+-PEG-RGDS nanoparticles on both Hep-G2 and HeLa cells was determined, confirming no adverse effect on their survival and proliferation. The interaction of the nanoparticles with Hep-G2 cells was monitored by confocal microscopy at both 808 and 980 nm excitation. The NaYF4:Yb3+/Er3+@NaYF4:Nd3+-PEG-RGDS nanoparticles were localized on the cell membranes due to specific binding of the RGDS peptide to integrins, in contrast to the NaYF4:Yb3+/Er3+@NaYF4:Nd3+-PEG-Alk particles, which were not engulfed by the cells. The NaYF4:Yb3+/Er3+@NaYF4:Nd3+-PEG-RGDS nanoparticles thus appear to be promising as a new non-invasive probe for specific bioimaging of cells and tissues. This development makes the nanoparticles useful for diagnostic and/or, after immobilization of a bioactive compound, even theranostic applications in the treatment of various fatal diseases.

Dataset Information

Fabrication of Au-Ag nanocage@NaYF₄@NaYF₄:Yb,Er Core-Shell Hybrid and its Tunable Upconversion Enhancement.

Publications

Fabrication of Au-Ag nanocage@NaYF<sub>4</sub>@NaYF<sub>4</sub>:Yb,Er Core-Shell Hybrid and its Tunable Upconversion Enhancement.

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